1. Field Of The Invention
The present invention relates to golf clubs, and in particular, to a set of irons having a progressive weighting system in which the weighting or mass of each club is adjusted or varied depending on the particular club within the set.
2. Description Of The Related Art
Traditional iron club heads were made of forged carbon steel, which in essence is a hot piece of metal that is stamped at great force through hydraulics to form a club into a desired shape.
In the early 1970's, a process was designed for investment cast steel to be shaped in the configuration of a golf club head. Specifically, a mold is made and liquid metal is poured into the mold and allowed to harden. The metal is then finished to have the desired features. One benefit enjoyed by iron golf clubs made from this process is that one is able to easily distribute weight or mass to the desired locations. Since forged carbon steel required large forces to stamp the metal, it presented many limitations with regards to distributing weight around the club head. However, with investment casting, one is able to design a mold having sharp angles, corners and other requirements which facilitate the desired weight distribution. When investment cast irons were first introduced, "perimeter-weighting" was a much publicized feature. Specifically, in a perimeter-weighted iron club head, the weight or mass is concentrated on the outer perimeter of the golf club so that weight or mass could be evenly distributed around the entire club head. This essentially expanded the size of the center of percussion or "sweet spot" of the club face, thereby allowing the club head to be more "forgiving" to shots that were hit off-center. In a typical perimeter-weighted iron, the weighted perimeter would also define a cavity in the rear of the club head, so these clubs were also commonly referred to as "cavity-back" irons.
Notwithstanding the above developments, numerous attempts were still made to distribute the weight or mass around different areas of an iron club head to achieve particular objectives. For example, attempts were made to provide discrete weights at specific areas of the club head, as illustrated in U.S. Pat. Nos. 1,089,881 to Taylor, Jr., 4,650,191 to Mills, 4,754,977 to Sahm, 5,100,146 to Antonious, and 5,280,911 to Katayama.
Other attempts have focused on providing a cavity-back perimeter-weighted club head with secondary weight members provided within the cavity, as illustrated in U.S. Pat. Nos. 4,826,172, 4,919,430, 4,932,658, 4,938,470, 5,014,993, and 5,046,733, all to Antonious.
Further attempts have included modifications to the sole of the club head, as illustrated in U.S. Pat. Nos. 3,862,759 to Evans et al. and 5,125,662 to Antonious.
Other attempts have been made to redistribute the weighting of a club head. For example, U.S. Pat. No. 5,297,803 to Solheim provides a perimeter-weighted club head in which the weight or mass along the perimeter is varied at different locations. U.S. Pat. No. 5,026,056 to McNally et al. provide a pair of weight pads 57, 58 inside the back cavity of the club head, the pads 57, 58 progressively changing configurations through the successively lofted clubs, from the two-iron to the wedges, to redistribute the weight in each club's back cavity to have each club's center of gravity positioned directly behind the club head's center of percussion. JP 5-49714 to Katayama describes a set of iron club heads having a plurality of ribs positioned in the back of the club head, with the weight of the ribs varied depending on the club to increase the depth of the center of gravity of each club head and the moment of inertia around the center of gravity.
Notwithstanding the above-described efforts and improvements, there still remains a need for an iron club head which assists the average golfer in hitting the ball further and more accurately.